AI 中文总结
本文针对多变换器系统大信号稳定性评估难题，引入类小增益特性构建相关框架，通过建立模型确定稳定区域，经并联及四变换器系统验证，可实现定量稳定性评估。
AI 中文摘要
并网换流器渗透率的大幅提升极大改变了电力系统的大信号特性，其由各类控制算法塑造的角度动态特性，以及通过复杂电路耦合形成的特性，给多变换器系统的大信号稳定性评估带来了重大挑战。为解决该问题，本文引入小增益定理（该定理通过子系统各自的耗散能力刻画互联系统的耗散能力，即类小增益特性），以研究多变换器系统的暂态角度运动。首先构建包含一组互联相对角度运动的大信号模型，随后在特定角度范围内为多变换器系统建立类小增益特性，进而可构造李雅普诺夫函数。基于此，在角度限制区域内确定一个椭球形前向不变区域，该区域可作为多变换器系统大信号稳定区域的有效估计。将该方法进一步应用于并联系统和四变换器系统，明确计算出大信号稳定边界并通过实验验证。所提基于类小增益的大信号稳定性评估方法可对采用各类控制算法的多变换器系统进行定量稳定性评估，有望为现代电力系统的大信号稳定性评估及参数设计提供可扩展框架。
英文摘要
The increasing penetration of grid-connected converters has greatly altered the large-signal behavior of power systems. Their angle dynamics, shaped by diverse control algorithms and coupled through complex circuit interactions, pose substantial challenges to large-signal stability evaluation of multi-converter systems. To resolve this issue, the small-gain theorem, which characterizes the dissipation capability of interconnected systems (the small-gain-like property) via the individual dissipation capabilities of subsystems, is introduced to investigate transient angle motions in multi-converter systems. A large-signal model involving a set of interconnected relative angle motions is first developed, and the small-gain-like property is then established for multi-converter systems within certain angle limits, which further enables the construction of Lyapunov functions. Based on this, an ellipsoidal forward-invariant region is identified inside the angle-limit region, which serves as an effective estimate of the large-signal stability region for multi-converter systems. The method is further applied to a paralleled system and a four-converter system, where the large-signal stability boundaries are explicitly computed and subsequently validated through experiments. The proposed small-gain-like based large-signal stability evaluation method enables quantitative stability assessment in multi-converter systems with diverse control algorithms, which may provide a scalable framework for large-signal stability evaluation and parameter design in modern power systems.
Comments13 pages, 10 figures, 4 tables
